Somatic cells and white blood cells share important roles in the body, yet they differ in structure and function. In milk, somatic cells help monitor mammary health. Researchers found a strong link between somatic cell count and mastitis in dairy cows. The table below shows findings from recent studies:
Study Title
Findings
Association between somatic cell count or morbidity of chronic subclinical mastitis and longevity in dairy herds in Eastern Hokk…
Positive correlation between herd somatic cell count and chronic subclinical mastitis morbidity.
Cow-level risk factors associated with the increase in somatic cell count and the occurrence of subclinical mastitis in Brazilia…
SCC increases with higher parity and days in milk, indicating a link to mastitis incidence.
Metataxonomic analysis and host proteome response in dairy cows with high and low somatic cell count
Differences in proteomes of somatic cells from quarters with high and low SCC suggest a biological basis for mastitis incidence.
Why do these differences in milk matter for health and disease?
Key Takeaways
Somatic cells are crucial for tissue growth and repair. They help maintain healthy organs and can signal infections when their numbers rise in milk.
White blood cells protect the body from infections. Monitoring their levels in milk helps farmers detect health issues in dairy cows early.
High somatic cell counts in milk often indicate mastitis, a common infection in dairy cows. Regular testing can prevent severe health problems.
Different types of white blood cells in milk, like neutrophils and lymphocytes, have specific roles in fighting infections and supporting immune health.
Understanding and tracking somatic and white blood cell counts in milk leads to better herd management and improved milk quality.
Somatic Cells and White Blood Cells
Somatic Cells Defined
Somatic cells make up most of the tissues and organs in mammals. These cells exclude sperm and egg cells. They divide by mitosis, which allows the body to grow and repair itself. Somatic cells can change genetically after conception, but these changes do not pass to offspring. Scientists call these changes somatic variants. Some variants may lead to diseases such as cancer.
Somatic cell count in milkplay a vital role in monitoring mammary health. When a cow develops mastitis, the number of somatic cells in milk increases. This rise helps veterinarians detect infections early. The most common somatic cells in milk include epithelial cells and several types of immune cells. The table below shows the main types of somatic cells found in mammalian tissues and their origins:
Type of Somatic Cell
Origin
Skin cells
Ectoderm
Satellite cells
Mesoderm
Intestinal stem cells
Endoderm
Hematopoietic stem cells
Mesenchymal
Liver stem cells
Endoderm
Nervous system cells
Ectoderm
Note: Somatic cells represent the most abundant cell type in the adult animal body. They possess their own copies of the genome, except for red blood cells.
White Blood Cells Overview
White blood cells protect the body from infections and diseases. These cells originate from hematopoietic stem cells in the bone marrow. They belong to different lineages, such as myeloid and lymphoid cells. White blood cells play a key role in the immune system.
Milk contains several types of white blood cells, especially during mastitis. Neutrophils act as the first responders to infection in milk. They target bacteria and fungi. Eosinophils help fight bacteria and parasites and participate in allergic reactions. Basophils release histamine during inflammation. Lymphocytes include B cells, which produce antibodies, and T cells, which kill infected cells and remember pathogens. Monocytes clean up dead cells and debris.
First responders to infections, primarily targeting bacteria and fungi.
Eosinophils
Combat bacteria and parasites, and are involved in allergic reactions.
Basophils
Release histamine during allergic responses and inflammation.
Lymphocytes
B cells produce antibodies; T cells kill infected cells and remember pathogens for future defense.
Monocytes
Clean up dead cells and debris in the immune system.
Neutrophils dominate the white blood cell population in milk during mastitis.
Eosinophils and basophils appear less frequently but still contribute to the immune response.
Tip: Monitoring the types and numbers of white blood cells in milk helps farmers and veterinarians assess mammary health and detect infections early.
Functions in the Body
Somatic Cells’ Roles
Somatic cells perform essential tasks throughout the body. They maintain tissue structure and support organ function. In mammals, these cells divide by mitosis, which allows tissues to grow and repair after injury. Somatic stem cells play a critical role in tissue maintenance and repair. They self-renew and respond to signals from damaged areas. When injury occurs, somatic stem cells migrate to the site and replace lost or damaged cells. Chemokines guide these cells to the correct location. The rapid division of somatic cells near injury sites restores tissue structure and function. This process is vital for wound healing and regeneration.
Somatic stem cells maintain and repair tissues through self-renewal.
In skeletal muscle, these cells activate after injury and migrate to damaged areas.
Chemokines from injured tissues guide somatic cells to the site.
Somatic cells promote new blood vessel formation, which enhances healing.
Mitosis generates new cells to replace those lost or damaged.
Rapid cell division near injury sites restores tissue function.
Somatic mutations can lead to cancer and chronic diseases, affecting organ function.
Mutations accumulate with age and may contribute to organ decline.
Some mutations are tolerated, but others impair organ health.
In milk, somatic cells help monitor mammary health. Their numbers increase during mastitis, which signals infection in the mammary gland. Veterinarians usesomatic cell counts in dairy productionto detect mastitis early and protect animal health.
Note: Somatic cells play a key role in tissue repair, organ function, and disease prevention. Their activity supports overall health in mammals.
Immune Response of White Blood Cells
White blood cells defend the body against infection. They use several mechanisms to identify and eliminate pathogens. Phagocytes, such as neutrophils and macrophages, seek out and ingest harmful microbes through phagocytosis. Leukocytes exit the bloodstream via extravasation, which allows them to reach infected tissues. Complement factors and cytokines initiate this process. Neutrophils migrate to infection sites and destroy bacteria using phagocytosis. These cells also release toxic molecules and enzymes to clear infections. Neutrophils form neutrophil extracellular traps (NETs), which trap and kill pathogens with antimicrobial proteins.
Phagocytes ingest and kill pathogens through phagocytosis.
Leukocytes leave the bloodstream to reach infected tissues.
Neutrophils release toxic molecules and form NETs to eliminate pathogens.
Antibodies bind to antigens on pathogens, neutralizing them and marking them for destruction.
Lymphocytes circulate in the lymphatic system and actively seek out pathogens.
The spleen filters blood and supports immune responses by detecting and consuming pathogens.
Neutrophils degranulate, releasing enzymes that help clear infections.
Different types of white blood cells coordinate their responses through signaling pathways. The immune system relies on the activity of these pathways rather than specific cell types. Eleven modules of immune response have been identified, each characterized by signaling proteins. This coordination ensures a rapid and effective defense against infection.
In milk, neutrophils act as first responders during mastitis. Their numbers rise sharply when infection occurs in the mammary gland. Monitoring neutrophils in milk helps assess mammary health and detect mastitis early. The immune response in milk protects the mammary gland and supports overall health in dairy animals.
Tip: Tracking white blood cells in milk provides valuable information about mammary health and infection status.
Structure Comparison
Somatic Cells Structure
Somatic cells show remarkable diversity in structure across different tissues. In the mammary gland, these cells include epithelial cells and immune cells that enter milk during inflammation. The architecture of somatic cells depends on their tissue type and function. For example, epithelial cells in the mammary gland form tight layers that help produce and secrete milk. When mastitis occurs, immune cells such as neutrophils migrate into milk, changing the overall cell composition.
The structure of somatic cells varies with tissue type and age. The table below highlights genetic variation observed in different tissues:
Tissue Type
Genetic Variation Observed
Blood Cells
Age-related structural variation
Brain
Aneuploidy and retrotransposition
Preimplantation
Aneuploidy
Liver and Intestine
High numbers of observed somatic events in dividing tissues
Somatic mutations include single-nucleotide substitutions, repeat instabilities, and copy number variations.
The distribution of these mutations differs among tissues.
Tissues tolerate mutations differently based on their roles.
Tissue architecture helps protect against mutation accumulation. In tissues with geometric arrangement or cellular differentiation, mutations that do not occur in stem cells rarely persist. This reduces the overall mutation rate and helps maintain healthy milk production.
White Blood Cells Structure
White blood cells display unique structural features that support their immune functions in milk. Each type of white blood cell has a distinct nucleus shape and staining color, which helps scientists identify them under a microscope. The table below summarizes key features:
Type of White Blood Cell
Nucleus Structure
Staining Color
Eosinophils
Bi-lobed
Pink or Red
Basophils
Bi-lobed
Blue or Purple
Neutrophils
Multi-lobed (3-5)
Pale Pink
Monocytes
C-shaped
Blue-gray
Lymphocytes
Spherical
N/A
Neutrophils, which dominate the immune response in milk during mastitis, have multi-lobed nuclei and pale pink staining. Monocytes appear larger, with kidney bean-shaped nuclei and blue-gray cytoplasm. Lymphocytes are smaller, with round, densely-staining nuclei. The table below compares their size, nucleus shape, lifespan, and function:
White blood cells in milk change in number and type during infection. Neutrophils increase rapidly, helping to fight bacteria and restore mammary health. The structure of these cells allows them to move through tissues and respond quickly to threats in milk.
Note: The unique structures of somatic cells and white blood cells in milk reflect their specialized roles in health and disease.
Somatic Cells in Milk
Mastitis and Somatic Cell Counts
Somatic cell count score plays a crucial role in monitoring mammary health. Researchers have found that higher somatic cell count in milk strongly correlates with the presence of mastitis. During mastitis events, both the concentration and total daily output of somatic cells increase significantly. This rise helps veterinarians detect infections early and take action to protect dairy cows.
Milk cell counts vary greatly between healthy and infected mammary glands. In healthy milk, somatic cell count ranges from 16 to 614 cells per microliter. In infected milk, the count jumps to between 572 and 17,588 cells per microliter. This dramatic difference highlights the importance of regular milk cell counts for early detection. A significant gap in values exists between healthy and infected samples, making somatic cell count a reliable indicator for mastitis.
Regular monitoring of milk somatic cell counts allows farmers to identify problems before they become severe. Early intervention can prevent the spread of infection and improve overall herd health.
Clinical Mastitis Indicators
Clinical mastitis presents clear signs that can be detected through changes in milk and somatic cell counts. Veterinarians use milk cell counts to diagnose both clinical and subclinical mastitis. In asymptomatic samples, somatic cell count ranges from 35,000 to 490,000 cells per milliliter. Clinical mastitis samples show much higher counts, from 310,000 to 6,600,000 cells per milliliter. About 37.8% of asymptomatic samples have high counts, indicating subclinical mastitis. A somatic cell count of 250,000 cells per milliliter or more signals subclinical mastitis.
The following table summarizes the most reliable clinical signs of mastitis in dairy cows:
Clinical Signs of Mastitis
Description
Udder Condition
Swollen, red, and hot to the touch
Milk Appearance
Watery, contains flakes or clots, or has a yellowish color
Pain Response
Kicking during milking or reluctance to be milked
Systemic Effects
Fever and decreased appetite
Other Symptoms
Diarrhea and dehydration
Severity
Severe cases can be fatal
Milk somatic cell counts also help veterinarians distinguish between healthy and infected states. In healthy milk, macrophages and lymphocytes dominate. In infected milk, neutrophils become the main cell type, reflecting an active immune response.
Mammary Health and Somatic Cell Counts
Differential Somatic Cell Counts
Differential somatic cell counts play a vital role in evaluating mammary health in dairy cows. These counts measure the proportions of different cell types, such as neutrophils, in milk. When a cow develops an infection, the number of neutrophils in milk rises sharply. This change helps veterinarians and farmers distinguish between healthy and infected mammary glands. Researchers use advanced instruments, like the CombiFoss 7 DC, to determine both total and differential somatic cell counts in milk samples. The following table summarizes how differential somatic cell counts are used in practice:
Aspect
Description
Purpose
To estimate the variation of differential SCC and SCC in milk samples based on infection status, parity, quarter location, and days in milk.
Methodology
SCC and differential SCC are measured using specialized instruments, with bacteriological culture for confirmation.
Findings
Differential SCC provides insights into udder health and helps identify intramammary infections.
This method proves effective in both cows and sheep, showing broad applicability.
Receiver-operating characteristic (ROC) curve analysis helps define accurate thresholds for early detection of infection.
Health Monitoring
Farmers and veterinarians rely on somatic cell counts in milk to monitor mammary health and detect mastitis early. Elevated somatic cell counts signal inflammation in the mammary gland, often caused by infection. The presence of intramammary infections leads to much higher mean somatic cell counts compared to healthy quarters. Early detection allows for prompt treatment, reducing the risk of severe disease and improving overall health.
Several tools help monitor somatic cell counts in milk:
A somatic cell count tester provides quick and reliable results, making it easier to identify cows at risk. Early milk total and differential cell counts can effectively identify cows with intramammary infections. Different regions set specific thresholds for somatic cell counts in milk to indicate possible infection:
Region
SCC Threshold (cells/ml)
European Union
≥ 200,000
Australia
≥ 250,000
New Zealand
≥ 150,000
Early diagnosis using somatic cell count test kit is essential for effective mastitis treatment and maintaining herd health.
Summary
Key Differences
Somatic cells and white blood cells differ in both function and structure, especially when observed in milk. Somatic cells include a variety of cell types such as epithelial cells and immune cells. White blood cells, or leukocytes, represent a specialized group that defends the body against infection. In milk, somatic cells provide a snapshot of mammary gland status. White blood cells, particularly neutrophils, increase during mastitis, signaling an immune response.
The following table highlights how these differences impact diagnosis and management of mammary health:
Aspect
Impact on Diagnosis and Management
Somatic Cell Counts (SCC)
SCC offers a baseline for detecting subclinical mastitis in milk, but results can vary with lactation and parity.
Overuse of antibiotics in milk management increases costs and resource depletion; targeted diagnostics help prevent this.
Somatic cell counts in milk help identify infections early. Differential counts provide more detail, improving treatment decisions and reducing unnecessary antibiotic use.
High somatic cell counts in milk link to lower production and fertility, making timely intervention important.
Regular testing of milk prevents subclinical mastitis, which can reduce herd productivity without obvious symptoms.
Understanding somatic cell counts in milk supports better management, healthier animals, and improved milk quality.
Regular analysis of milk for somatic cell counts and white blood cell types strengthens herd management and supports animal health.
Conclusion
Somatic cells include both milk-producing cells and immune cells. They help identify intramammary infections and support tissue health. White blood cells, or leukocytes, act as the body’s defense system. They patrol for pathogens and respond to infections, which is vital for maintaining mammary health.
Monitoring somatic cell counts in milk improves disease prevention and herd management.
Individual cow monitoring reveals high counts in milk, even when cows show no symptoms.
Small herds benefit from identifying cows with high somatic cell counts in milk, leading to better milk quality.
High somatic cell counts in milk link to increased mastitis, with every 100,000 cells/ml rise in milk causing an 8-10% increase in infected cows.
Regular analysis of milk supports healthier animals and higher milk quality. Increased awareness of cell health and diagnostic tools helps protect dairy herds and ensures safe milk for consumers.
FAQ
What Is the Role of Somatic Cell Counts in Milk From Healthy Cows?
Somatic cell counts in milk from healthy cows help monitor mammary gland health. Farmers use these counts to detect early signs of infection. Regular testing supports healthy cows and improves milk quality. High counts may indicate problems in the mammary gland.
How Do Leucocytes in Milk Indicate Mammary Gland Health in Cows?
Leucocytes in milk show the immune response in the mammary gland. Healthy cows have low leucocyte levels in milk. When infection occurs, leucocyte numbers rise. Veterinarians check milk samples for elevated leucocytes to assess mammary gland health and identify unhealthy cows.
Why Does Neutrophil Percentage Matter in Milk Testing for Healthy Cows?
Neutrophil percentage in milk helps identify infection in the mammary gland. Healthy cows show low milk neutrophil percent. Elevated neutrophils signal an active immune response in the mammary gland. Farmers use neutrophil percentage to track healthy cows and improve scm management.
How Can Differential Somatic Cell Counts Improve Mammary Gland Health In Cattle?
Differential somatic cell counts allow farmers to measure neutrophil percentage and other cell types. Healthy cows show balanced counts. Cattle with infection display higher milk neutrophil percent. This method supports cellular immunity and helps maintain healthy mammary gland function.
What Are the Signs of Infection in Milk from Healthy Cows?
Milk from healthy cows appears clean and has low somatic cell counts. Infection causes changes in milk, such as increased neutrophil percentage and leucocytes. Farmers notice changes in milk quality and mammary gland condition. Early detection protects healthy cows and supports herd health.
